This will be much easier in LimeSurvey 1.92, which uses
ExpressionManager.
Say your question about fruit is Q1, a "Multiple Choice Checkbox" type question (type M), with sub-questions A-J (for 10 different fruit).
The relevance for your follow-up question would be:
sum(Q1_A=="Y", Q1_B=="Y", ..., Q1_F=="Y") > 1
And the question could be:
You said you liked the following fruit: {implode(", ", Q1_A, Q1_B, Q1_C, ... Q1_F)}. Which do you like best?
The same strategy would work if you asked the questions across several pages - you'd just have different variable names.
This also works on the same page - so you could have the text of Q2 be dynamically updated as people change their answers to Q1.